Ordnance breech mechanism



A. T. DAWSON AND G. T. BUCKHAM.

ORDNANCE BREECH MECHANISM.

APPLICATION FILED Aue.13, 1918.

miiiiimli Patented Dec. 30, 1919.

2 SHEETSSHEET A. T. DAWSON AND G. T. BUCKHAM.

()RDNANCE BREECH MECHANISM.

APPLICATION FILED AUG.13. 19m.

1;326,71 2, Patented Dec. 30, 1919.

2 SHEETSSHEET 2.

j awwwtou UNITED STATES PATENT OFFICE.

ARTHUR TREVOR DAWSON AND GEORGE THOMAS BUCKI-IAM, OF WESTMINSTER, LONDON, ENGLAND, ASSIGNORS TO UNITED STATES ORDNANCE COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION OF VIRGINIA.

ORDNANCE BREECH MECHANISM.

To all whom it may concern:

Be it known that we, Sir ARTHUR TREVOR DAWSON, knight, and Sir Gnoncn THOMAS BUCKHAM, knight, both subjects of the King of Great Britain, residing at Vickers House Broadway, Westminster, in the county 0 London, England, have invented certain new and useful Improvements in or Relating to Ordnance Breech Mechanism, of which the following is a specification.

This invention relates to ordnance breech mechanism of the swinging carrier type having a breech block or screw arranged around the breech end of the gun instead of within it as is usual; the improved breech mechanism is intended more particularly for use with ordnance of comparatively small caliber.

According to the invention there is interposed between the externally arranged breech screw and the breech end of the gun a cam device which, during the final portion of the closing movement of the carrier, serves to convert the swinging movement of the breech screw into angular locking movement to effect the locking of the breech screw and also serves during the unlocking movement of the breech screw to initiate the opening swinging movement of the carrier, as is well understood in other forms of breech mechanism. This cam device may comprise a cam groove cut in the breech end of the gun, and a pin or roller projecting inwardly from a flange on the breech screw engaging with this cam groove.

In order that thesaid invention may be clearly understood and readily carried into efi'ect we will describe the same more fully with reference to the accompanying drawings, in which:

Figures 1, 2 and 3 are respectively a rear elevation, a side elevation and a plan showing the breech end of a gun provided with our improved breech mechanism.

Fig. 4 is a section taken approximately on the line of Fig. 1.

Fig. 5, is a rear view partly in section with the breech locked, and

Fig. 6, is a plan view partly in section with the breech unlocked and swung rearwardly.

A is the breech end of the gun. A is the breech screw and a is a forwardly projecting flange thereon having internal inter- Specification of Letters Patent.

Application filed August 13, 1918.

Patented Dec. 30, 1919.

Serial No. 249,653.

rupted threads or collars for engaging with corresponding external interrupted threads or collars on the breech end of the gun. B IS the swinging carrier pivoted to the gun by the vertical hinge pin 6 which passes through the carrier and through hinge lugs a, a on the breech end of the gun. C is the breech actuating hand lever connected to the carrier by a transverse shaft C" which at its inner end has a crank pin C engaging with a slot a? in a rearwardly projecting cylindrical extension A of the breech screw; a is the aforesaid cam groove cut in the breech end of the gun and a is the pin or roller which projects inwardly from the breech screw flange a and engages with this cam groove.

When the breech actuating hand lever C is actuated to open the breech, the pin C anul-arly displaces the breech screw until its interrupted threads or collars come opposite the gaps between the interrupted threads or collars on the breech end of the gun. At this time the said hand lever comes against a stop on the carrier (this stop being constituted, for example, by the rear part of a guide b in which works a fin c" on the handlever C) and the mechanism then swings out above the hinge pin 6, this movement being initiated by the engagement of the aforesaid pin or roller a with the cam groove of. During this movement of the mechanism the breech screw is prevented from becoming angularly displaced about its axis toward the locking position by the engagement of a projection A on the breech screw with the upper surface of the lower one of the hingle-lugs a, a on the breech end of the gun, the said projection coming opposite a gap a (Fig. 3) in the said hinge-lug when the carrier is in the closed position so that the said projection can then pass from one side to the other of the said hinge-lug during the locking and unlocking of the breech screw. If desired the projection A might be so situated as to engage in a similar manner with the upper instead of the lower hinge-lug.

During the closing of the breech, the breech screw is unable to become angu larly displaced about its axis until the projection A comes opposite the gap a in the lower hinge-lug whereupon the pin or roller a on the flange a of the breech screw comes into engagement with the cam oove a in the breech end of the gun, thus imparting rotary locking motion to the breech screw, the energy derived from the closing movement of the mechanism being usually sufficient to fully lock the breech screw.

What we claim and desire to secure by Letters Patent of the United States is 1. Ordnance breech mechanism comprising in combination an externally arranged breech screw and a cam device interposed between the breech screw and the breech end of the gun.

2. Ordnance breech mechanism comprising an externally arranged breech screw having a forwardly projecting flange provided with internal interrupted threads @1- gageable with corresponding external interrupted threads on the breech end of the gun, and an inwardly projecting cam follower on the flange engaging with a groove on the breech end of the gun.

3. Ordnance breech mechanism as set forth in claim 1, wherein the breech screw is prevented from becoming displaced toward its locking position during the opening and closing movements of the carrier by the engagement of a projection on the breech screw itself with one of the hinge lugs of the breech screw carrier.

ARTHUR TREVOR DAWSON. GEORGE THOMAS BUOKHAM. 

